g(m1)-ganglioside and Neuritis

Multifocal motor neuropathy (MMN) is now a well-defined purely motor multineuropathy characterized by the presence of multifocal partial motor conduction blocks (CB), frequent association with anti-GM1 IgM antibodies, and usually a good response to high-dose intravenous immunoglobulin (IVIg) therapy. However, several issues remain to be clarified in the diagnosis, pathogenesis, and therapy of this condition including its nosological position and its relation to other chronic dysimmune neuropathies; the degree of CB necessary for the diagnosis of MMN; the existence of an axonal form of MMN; the pathophysiological basis of CB; the pathogenetic role of antiganglioside antibodies; the mechanism of action of IVIg treatments in MMN and the most effective regimen; and the treatment to be used in unresponsive patients. These issues are addressed in this review of the main clinical, electrophysiological, immunological, and therapeutic features of this neuropathy.

Topics: Animals; Autoantibodies; G(M1) Ganglioside; Humans; Immunoglobulins, Intravenous; Motor Neuron Disease; Motor Neurons; Neural Conduction; Neuritis; Peripheral Nerves

Most inflammatory neuropathies, both acute and chronic, probably result from an immune attack against antigens of the peripheral nervous system. Specific antibodies in serum that react with the peripheral nervous system have been described in a number of inflammatory neuropathies. We review the pathophysiological significance of auto-antibodies and discuss their use for the diagnosis of patients with peripheral neuropathy.

Topics: Ataxia; G(M1) Ganglioside; Humans; Immunoassay; Immunoglobulin M; Motor Neurons; Neuritis; Paraproteinemias; Peripheral Nervous System Diseases

A 46-year-old male patient reported difficulties in speech and swallowing following gastroenteritis. Marked open nasality (open rhinophonia) and swallowing difficulties with occasional passing of food into the nasopharynx was observed during speaking with the head held in an upright position. The patient was able to articulate clearly with the head reclined or in a lying position. Endoscopy identified complete bilateral soft palate paresis consistent with bilateral glossopharyngeal nerve palsy. Additional symptoms of cranial nerve palsy appeared in the course of the disease. Intravenous corticosteroids were ineffective. A marked improvement of symptoms was achieved after i.v. immunoglobulin therapy that was initiated following identification of serum IgM anti-GM 1 ganglioside antibodies under suspicion of cranial polyneuritis. Nasality was largely resolved under additional speech exercise therapy.

Topics: Articulation Disorders; Autoantibodies; Cranial Nerve Diseases; Deglutition Disorders; Diagnosis, Differential; G(M1) Ganglioside; Glossopharyngeal Nerve Diseases; Humans; Immunization, Passive; Immunoglobulin M; Male; Middle Aged; Neuritis; Palate, Soft; Voice Disorders

Anti-GM1 antibody may function in disease development in some patients with Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy and multifocal motor neuropathy. Intravenous immunoglobulin (IVIg) therapy is effective in these neuropathies, but the mechanism by which IVIg acts is not clear. To test whether it has anti-idiotypic activity on anti-GM1 antibody, we investigated whether IVIg inhibits the binding of cholera toxin to GM1. It inhibited the reaction between cholera toxin and GM1 mediated by F(ab')2 fragments of IgG. Treatment with sialidase did not inhibit the binding of cholera toxin to GM1, whereas denaturation with guanidine did. This suggests that the GM1 epitope in IVIg has peptide and not carbohydrate structures. The variable region of IVIg may bind to anti-GM1 antibody, as well as to cholera toxin, thereby neutralizing the pathogenic effects of the autoantibody.

Topics: Antigen-Antibody Reactions; Autoantibodies; Cholera Toxin; G(M1) Ganglioside; Humans; Immunoglobulins, Intravenous; Kinetics; Neuritis; Polyradiculoneuropathy